To cite package 'guess' in publications use:

Sood G, Cor K (2016). guess: Guessing Adjusted Estimates of Learning.. R package version 0.1.

Corresponding BibTeX entry:

  @Manual{,
    title = {guess: Guessing Adjusted Estimates of Learning.},
    author = {Gaurav Sood and Ken Cor},
    year = {2016},
    note = {R package version 0.1},
  }